Option key not working at boot up. Mac Pro mid 2012 quad core intel xeon. key board works fine on iMac. reset SMC. reset Pram. erased hard drive and installed Sierra. was running Mojave. seems like it does not see key board soon enough. reboot and tap caps lock, cap light did not come on until late in boot up. Also when I boot on iMac and hold option key at chime, the screen turns a light color. Mac Pro stays dark.